1. Field of the Invention
The present invention relates to a method for analyzing secretome, a biomarker for lung cancer metastasis, and a siRNA compound for inhibiting lung cancer metastasis and, more particularly, to a method for analyzing secretome related with cancers, a biomarker for lung cancer metastasis obtained from the aforementioned method, and a siRNA compound for inhibiting lung cancer metastasis which is developed from the aforementioned biomarker.
2. Description of Related Art
Cancer metastasis is a very complicated process, and is a main causal factor in cancer deaths. During the process of cancer metastasis, tumor cells are first separated from original foci and subsequently invade into peripheral blood vessels or lymphatic vessels. Then, the separated tumor cells transfer to other organs through the circulatory system or lymphatic system, and develop tumor cells on other organs.
Many studies have found that secretome plays an important role in inducing tumor cell migration and invasion during the cancer metastasis process, and increases the probability that cancer cells migrate to other organs though an extracellular matrix. Hence, if the proteins from the secretome related to the cancer metastasis can be identified, the obtained proteins can be used to evaluate the risk of cancer metastasis and potentially inhibit cancer metastasis.
Recently, many secretome analytic methods have been developed to analyze the proteome secreted from cells. These methods are performed by purifying secretome, and analyzing the purified secretome with LC-MS/MS. However, there are high-concentrated salts and many contaminants contained in the secretome sample, and the matrix in the medium may influence the results of sequential mass spectrometry analysis.
In addition, many exosomes, glycoproteins and transmembrane proteins are contained in the secretome. These proteins are hard to separate or digest, and may influence the results of analysis. Even though these proteins can be separated or digested, the chemical compound in the reagent for separation or digestion may also deteriorate the liquid chromatography system. Hence, there are no effective methods to effectively analyze secretome from cells.
Secretome is highly related to cancer metastasis. Furthermore, if an effective method for analyzing secretome can be developed, proteins related to cancer metastasis can be identified through this method, and the identified proteins can further be applied in evaluation or inhibition of cancer metastasis.
The mortality (death rate) from lung cancer is among the highest of all cancers, and the risk of suffering from lung cancer in Taiwan is higher than other countries. According to the data published by Department of Health in Taiwan, lung cancer is the most common cause of local cancer-related death. Hence, if the proteins related to lung cancer metastasis can be identified from secretome, the mortality from lung cancer may further be reduced.